Mechanical stoker



No. 6|6,009. Patented Dec. I3, |898. J. F.' PO0L;

MECHANICAL STOKER.

(Application lod July 10, 1897.)

4 Shank-Sheet I.

(No Model.)

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MECHANICAL STOKER.

(Application led July 10, 1897.)

4 Sheets-Sheet 2.

(N0 Model.)

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No. 6l6,009. Patented Dec. I3, |898. J. F. POOL.

MECHANICAL STOKER.

` (Application led July 10, 1897.) (No Model.) 4 Sheets-fSheet 3.

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Patented D-ec. I3, |898.

4 `Sheetsf-Sheet 4.

No. 6l6,009.

.1. F. Pom. ME'GHNIGAL STOKEH.

(Application lsd July 10, 1897.)

(No Model.)

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NTTED STATES PATENT OFFICE.

JOHN F. POOL, OF PHILADELPHIA, PENNSYLVANIA.

MECHANICAL STOKER.

SPECIFICATION forming part of Letters Patent No. 616,009, dated December13, 1898.

Application met my 1o, 1897.

To @ZZ whom t may concern:

Be it known that I, JOHN F. POOL, a subject of the Queen of GreatBritain and Ireland, and a resident of Philadelphia, Pennsylvania, haveinvented certain Improvements in Mechanical Stokers, of which thefollowing is a specification.

The main objects of my invention are to insure regularity and uniformityof feed of the fuel to the grate-bars, to promote steady combustion, toinsure the durability and efficient action of the working parts of thestoker, to provide means for readilyadjusting the feed so as to adapt itto the requirements of the fuel which is being burned, and to permit ofthe ready renewal of the gratebars, the general purpose of the inventionbeing to burn with economyloW-grade fuels, to avoid the formation ofsmoke, to auto-- matically handle the fueland ashes, and to use fuelthat burns either from above or below.

In the accompanying drawings, Figure l represents a longitudinal sectionof a mechanical stoker constructed in accordance with my invention. Fig.2 is a front View of the same. Fig. 3 is a view partly in plan andpartly in sectional plan. Fig. 4is a side view of one of the movablegrate-bars. Fig. 5 is a plan or top view of the same. Fig. 6 is a sideview of the upper end of one of the stationary grate-bars. Fig. 7 is atransverse section of one of the grate-bars. Fig. 8 is a section of oneof the ash-dumping plates on a larger scale than Fig. l. Fig. 9 is atransverse section on the line of the shaft carrying the ash-dumpingplates, showing one of said dumping-plates and some of thegrate-barsupporting devices. Fig. 10 is a sectional view of theconnection employed between the operating-lever and the f nel-feeding or.grateoperating device, such section being on a larger scale than Fig.l. Fig. 1I is a transverse section on the line Fig. l0. Fig. 12 is atransverse section on the lineyy, Fig. lO. Fig. 13 is an enlarged viewof the upper end of one of the movable grate-bars, showing its relationto the furnace-front and deadplate;. and Fig. 14 is a similar View ofthe upper end of one of the fixed grate-bars.

ll represents the upperportion of the furnace-front, and 2 the lowerportion of the same, the latter being offset inwardly in respect to theupper portion and constituting a bearing for the heads 3 of the xedgrate- Serial No. 644,045. (No model.)

bars 4, the bars 4 being the movable bars and the heads 3 of said barsbeing supported upon the operating devices therefor, as hereinafter setforth. Y

Both sets of bars have toes at their lower ends, and these toes haveside walls with horizontal bottoms, which rest upon flanged collars 6and 6', mounted upon a shaft 7, which is adapted to suitable bearings inthe side walls of the furnace and is capable of having motion of partialrotation imparted to it Wheneversuch motion becomes desirable, one

end of the shaft projecting beyond one of the \with an internal mass ofgraphite or otherv heat-resisting lubricant, so that as the gratebarsare moved these supporting-collars can turn back and forth on the shaft,and thereby lessen the friction due to such movement.

The fixed grate-bars 4a alternate with the movable grate-bars 4, and theflanged collars which support said fixed grate-bars are by preferencesecured to `the .shaft 7, some of said collars forming part ofash-dumping plates I3, suitably perforated or slotted, and when in theirraised position forming a continuation of the upper surface of thegrate-l `bars, as shown in Fig. 1.

Those of the collars 6 which form part of the dumping-plates 13 arepreferably split and provided With ears which can be drawn together bymeans of a clamp-bolt, as shown in Fig. 8, so that they may be tightenedupon the shaft 7 and sei cured to keys let into the shaft, thus causingthe ash-dumping plate to move with said shaft.

To suitable brackets l5 on the upper portion of the fron-t plate of thefurnace is adapted a shaft 1G, which has an eccentric 17, with strap 18,connected' to a pin on a rightangled lever 19, theV latter', beingsuitably fulcrumed in a bracket 20 on the front plate, so that as theshaft 1G is rot-ated a IOO swinging movement will be imparted to saidlever.

Each of the arms of the lever 19 is forked for the reception of a block21, which is mounted so as to be free to turn with the transverse bolt22, which is adapted to bearings in the forked portion of the arm, bothblock and bolt being perforated for the passage of a rod 23, which has,outside of the block 21, a nut 24, and inside of said block anadjustablestop 25, so that by adjusting the latter to different positions on therod 23 more or less lost motion ofrthe block 2l between the nut 24 andthe stop will be permitted, and hence the extent of movement imparted tothe rod 23 by the lever 19 can be readily regulated.

Each of the stops 25 consists of a bolt 26, which has an opening for thepassage of the rod, and passes through apair of washers 27, embracingthe opposite sides of said rod and acted upon by a handled nut 2S,adapted to the threaded end of the bolt 2G. Hence by turning said nutbackward the hold of the washers 27 upon the rod 23 can be loosened andthe stop 25 adjusted to any desired position on the rod to be againlocked in position after adjustment by screwing up the nut 23 andtightening the washers upon the rod.

The rod 23 of one arm of the lever 19 is connected to an arm 30,depending Vfrom a :rock-shaft 31, which carries the heads 3 of themovable grate-bars 4, toothed segments 32 on said shaft 3l meshing withand supporting racks 33 on the under sides of the projecting heads 3 ofsaid movable grate-bars 4, so that the latter are constantly moved backand forth, the heads 3 being just free from contact with the upperportion of the furnacefront 2, so that there is no frictionalretardation of the movement of the bars. Continual agitation of the bedof fuel lying upon the grate-bars is thus effected in order to insurethe proper access of air thereto to support combustion and also toinsure the feeding of the mass of fuel downward on the grate-bars andthereby make room for the fresh fuel at the upper ends of saidgrate-bars and deliver the ashes from theirlower ends onto the plates13, which can be swung downward at interyals so as to dump the mass ofashes into the ash-pit or can be swung partially downward, so as towithdraw their ends to a greater or less distance from theA bridge-walland thus provide for a slow but continuous discharge of ashes into theash-pit. The other arm of the lever 19 is connected by its rod 23 to anarm 34 on a rock-shaft 35, mounted in suitable bearings in front of theupper plate of the f u mace-front, said rock-shaf t having near each enda segment 3G, split and secured to the shaft 35 by means of aclamping-bolt 37, said segments being connected by means of rods 3S to apusher-plate 39, which forms part of the bottom of a fuel-hopper 40,extending across the upper front plate of the furnace.

The forward end of the pusher-plate 39 carries antifriction-rollers 39a,bearing upon a dead-plate 41, which extends into the upper portion ofthe furnace and is in contact at its lower end with the heads 3 of thestationary grate-bars 4, so that there is a constant feeding or pushingforward of the fresh fuel from the bottom of the hopper iirst onto thedead plate and then onto the upper ends of the grate-bars, the fuelbeing maintained upon the dead-plate for a sufficient length of time toinsure the comparatively slow distillation therefrom of the morevolatile gases, which, passing through the highly-heated products ofcombustion arising from the incandescent fuel on the grate, are ignitedand consumed, so as to prevent the formation of smoke.

The dead-plate 41 rests upon the heads of the stationary gratesbars3,and upon an anglebar 42, extending transversely across the front ofthe furnace, and said plate can when the occasion arises be readilylifted from the tops of the grate-bars, so as to permit of thewithdrawal of any one of the latter when it becomes burned out orotherwise in need of repair or replacement. The inner end of thedead-plate is supported free from contact with the heads of the movablegrate-bars, and hence does not retard the movement of the same.

Each of the grate-bars is of inverted-U shape with slotted top andvertical side walls, as shown in Fig. 7, and the upper portion of eachof the side walls of each grate-bar is reduced in thickness at and nearthe top, this reduction in thickness preferably extending throughout thedepth of the top member of the bar, so that While the lower portions ofthe side walls of adjoining bars may be in contact with each other theupper portions of said side bars are separated by a space suilicient topermit of the lateral expansion and growth due to the heating of thisportion of the grate-bar without causing the bars to bind upon eachother, and thereby interfere with the movement of the movable bars ofthe grate. The upper portion of each of the contracted side walls ofeach grate-bar is also slotted, as shown at 43, Figs. 4, 5, and 7, so asto provide for longitudinal contraction and expansion of the uppersurface of the bar without causing the same to buckle or otherwisebecome distorted, the slots 43 gradually increasing in depth from eachend of the bar toward the center of the same, as shown in Fig. 4.

The heads of the fixed bars of the grate have lugs 46, engaging with thebearing bar or portion of the furnace-front, upon which said grate-barheads are supported.

My improved stoker can be used in connection with a furnace havingeither natural, induced, or'forced draft, the ash-pit doors iit tingsnugly to the lower portion of the front plate of the furnace and theheads of the gratebars being of box-like form and fitting snugly againsteach other, so that there is no undue leakage when the air is maintainedunder pressure in the ash-pit.

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As all portions of the bed of fuel are subjected to the same degree ofagitation and receive the same supply of air,itfollows that thecombustion is regular and uniform throughout the entire mass of fuelupon the grate, so that the maximum heatingvalue of the fuel isobtained, and fuels of inferior quality'can` be successfully used, theprovision of the dead-plate at the upper end of the grate-bars enablingme to partially coke or distil the volatile gases from the green fuelbefore the latter reaches the air-supplying portion of the grate,whereactive combustion begins. Hence the formation of smoke, such as is duetothe rapid distillation of volatile gases from a mass of green fuelthrown upon a highly-heated body of incandescent fuel, is eifectuallyprevented in my furnace, and the fuel, of whatever character, is burnedwithout any production of smoke or with atleast the minimum productionof it.

Having thus described my invention, I wish it to be understood that thesame is not limited to the exact construction illustrated, as manychanges within the knowledge of those skilled in the art may be madetherein without departing from the main features of my invention. Forinstance, the front plate may be made without the inward offset, and thegrate-bars may be supported upon a special bearing extending across thefurnace inside of the front plate, the rock-shaft 31 being also insideof the same, and the heads and toes of the grate-bars may be cast withsaid bars instead of being cast separable and bolted thereto, and theash-dumping plate may be made without its perforations or in the form ofa grate and may be carried by a shaft independent of that which supportsthe toes of the grate-bars, or many other immaterial variations of thischaracter may be made within the scope of my invention.

I claim as my invention and desire to secure by Letters Patentl. In amechanical Stoker, the combination of the front plate of the furnacehaving its lower portion offset inwardly in respect to the upperportion, a transverse opening being formed between the upper and lowerportions of the furnace-front, with the grate-bars supported at theirupper and lower ends and capable of being withdrawn from above throughsaid opening between the upper and lower portions of the furnace-frontand a dead-plate forming an upper continuation of the'gratebars andextending across the space between the offset portions of thefurnace-front, substantially as specied.

2. In a mechanical Stoker, the combination of inclined grate-bars andsupports therefor, with ya dead-plate forming an upward continuation ofthe grate-bars, a furnace-front having an opening through which thegratebars can be withdrawn, andv provision for mounting the dead-plateso that it can be raised above the heads of the grate-bars in order topermit of such withdrawal, subst-antially as specified. v 4

3. In a mechanical stoker, the combination of alternating fixed andmovable grate-bars,

'with a dead-plate forming an upward continuation of said bars, saiddead-plate resting upon the heads of the fixed grate bars, but beingfree from contact with the heads of the movable bars, substantially asspecified.

4. In mechanism for reciprocating the grate bar or pusher plate of amechanical stoker, the combination of the vibrated lever, with apower-transmitting rod having stops between which the end of theleverplays, one of said stops being adjustable on the rod and comprisinga bolt perforated for the passage of the rod, washers strung on saidbolt and embracing the opposite sides of the rod, and a nut adapted tothe threaded portion of the rod and bearing upon one of said washers,substantially as specified.

5. A grate-bar for furnaces having an inverted- U shape incross-section, the opposite side walls of the bar being reduced inthickness at and near the top, whereby the lower portions of the sidewalls of adjoining bars may be in contact without restricting thelateral expansion and growth of the upper portion of the bar,substantially as specified.

6. A grate-bar for furnaces consisting of a slotted or perforated bodyor central portion, and detachable head and toe portions, saidentire'series of grate-bars, with their head and toe portions havingvertical side walls, and all of the parts of the bars having the upperportions of said side walls reduced in thickness, substantially asvspecified.

7. A grate-bar for furnaces having an inverted- U shape incross-section, the upper member being slotted or perforated,withVertical side walls reduced in thickness at and near the top, andtransverse slots extendingstructure forming a continuation ofsaidgrate-bars, a shaft located under the lower ends of the grate-bars,and to which said ashdum-ping structure is secured, and provision formoving said shaft whereby the ash-dumping structure will swing down andaway from l the bridge-wall, substantially as specified.

9. In a mechanical stoker, the combination of the grate-bars,ash-dumping plates having collars which serve also as supports for thelower ends of the grate-bars, and a shaft to which said collars aresecured, substantially as specified.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHN F. POOL.

Witnesses:

Jos. I-I. KLEIN, FRANK E. BEcHToLD.

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